Improvement in joints for iron truss-bridges



JDITQ all whom it may concern-r. Be it known that I, EDWARD i I IMPROVEMENT INJQINTS on anon i nusseeuioe's'st 'EDwARn's. SHAW, or'cAiuBRIDG E, Mn-ssaonusnrrs January 6, 1875.

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Cambridge, inthe county of Middlcsex' and State of Massachusetts, have invented an An Y :nulate Joint for Iron Bridges and other en'- gineeringconstruction, of which the following is a specification:

My invention consists in a mode of joining 1 plates, bars, or otherwise shaped pieces of iron, steel, or other suitable metal, so that the g combination of bars or other shapes may withj gan a a stresgofi tension or compression of an iiitensity as great as could safely be imposed upon a single bar or piece of the same iraterial, and a joint is produced which may be -made flexible or rigid at will.

In order to describe and illustrate the construction of this joint, I will take-a simple case of joining, and will suppose that twoflat bars of iron, each measuring about four inches by one-half inch in section, are to be connected for the purpose of forming a continuous tensi'on member. I then proceed as follows: I bore through each plate, near its end, and in the middle of its broad face, a cylindrical aperture, circular in section. I next cut or stamp into one of the broad faces of each bar circular grooves or depressions, concentric with one another, and with the aperture which they encircle These grooves may be of semicircular section; or they may have 'a section. similar q I to a screw-thread of the Whitworth or Sellers pattern; or, indeed, they may be shaped in other forms; but at present I prefer those above mentioned. In case that I have cut channels of a semicircular section in the platefaces, I bend wires into 11in gs of size and section to fit the channels, and insert these rings in the channels. I then bring the bars'together, and confine them by a bolt contained in the eyes out in the plates, the heads or nuts r g of the bolt acting on the outer plate-faces, to

' draw'the plates together. But if I- have cut inthe plates channels of the screw-thread section close together, th as surrounding the eye a number of annnlets, I then prepare an annulated washer by 'taking a iece of toler- 7 ably thin plate of circular sha ie forming; an eye in its center, and cutting or stamping into the surface surronmling the eye, on each side I oi the plate, annulets of the screw-thread sec the eyes. j Figure l'shows an outside. view of this oint; Fig. 2, an outside-edgeview and section they may fit and engage with theannulets of the plates to be fastened together. Itheninterpose the washers, and bring the plates together, as before, by a bolt passing through through centerof platesjand Fig. 3, a view .and section of the'joint formed with rings.

Figs. 6 and 8show the annulations ofthe plate for the two modificationsof this joint. Fig. 5 shows a transverse section and face view of the annulated washer; Fig; 4, an enlarged section of a part of the washeryand Fig. 7.

the rings for the joint shown by Figs. 3 and 8.

STATEs Na-OFFICE j Specification forming part of Letters Fatenih'o. 159.046, dated January 26.187 .wPP l' 1 "f-tionfthepitch of whats; soadjnsted-that It .is seen, by'reference to Fig. 4, that the outer annulets of thewasheraretruncated,

and that the plates arecut to a correspondingly lessdepth in their outer annulations.

This is in order' to prevent a weakenin'g'ot' the plateby a deep outer cut. The same result is attained in the case of the joint formed with separate rings, bymaking the outer ring of smaller section than the inner ones.

I have described above thesimplest form of my invention that of a joint between two plates. It is evident that several plates may be joined by lappin g their extremities, 'cuttin g annulets on both broad faces of all plates except the outer ones,- and interposing a sufiicient number of rings or annulated washers. It is also evident that flat plates may be joined to fiat surfaces-of the ordinary rolled-iron shapes,kn own as I, T, L, channel irons, &c., or topieces or members of cast-iron,

whose ends; may be molded into annulated faces for this purpose. it

Fig. 9 shows the connection by::the annulate joint of a sing1e plate with two other plates of half its thickness. v

Fig. 10 shows a bridge-joint. 0 marks the tension-chord plates. uT marks plates either forming in themselves the diagonal ties, or to which the diagonal ties may be attached. '1 marks plates to which the post or vertical strut may be attached. V

Fig. 11 shows the attachment of plates to other plates and to angle-irons by the ann'u-I late joint, the combination forming a small trussed girder, and is self-explaining.

cutting or, molding and cutting w an action precisely analogous to that of a bolt upon its nut by means of the screw-thread,

' be made sufficiently and its action will then ;tothe joint the required strength.

The problem of the mechanical formation of the annnlets of the plates and washer is one of no great diffieulty. They'may be cut'by' the use of a chasing-tool set eccentrically in the chuck of a lathe, stamped with dies, formed in castings by impression of themold, or. formed by a combined process of stamping and The effectof the above-described, joint is to transfer the'stress from one bar to another by The invention above.described is the result of an investigation, instigated by a desire to produce a connection for the lower chords of bridges more simple, light, and economical than those now in use.

I do not Wish, however, to confine its application to bridges alone, but propose to use the joint in any engineering structure whereit may be scientifically or conveniently applicable as a connection.

What I claim as my invention, and desire to secure by Letters Patent, is

A- joint formed by cutting, stamping, or molding into the surfaces-of the parts connected concentric annular depressions or to be grooves, interposing rings or an annnlated washer, fitted to said depressions or grooves, and confining the surfaces in juxtaposition by a bolt contained. in eyes concentric with said depressions or grooves, and provided with g I suitable nuts or heads and washers, substan-' tially as and for the purposes described.

In testimon to this specification in the subscribing witnesses. v

' EDWARD S. SHAW.

presence' of two Witnesses:

J on. H. ADAMS, M. S. G. WILDE.

ywhereof I have signed my name I 

